Brake mechanism



F. H. RAGAN Zell BRAKE MEoHAnIsM Filed June 16. 1928 Snoentor Hedel-c fr.

attorneys Patented Dec. 115, 1931 UNITED STATES FREDERICK HATHAWAY RAG-AN, 0F CLEVELAND, OHIO BRAKE MECHANISM Application tiled .Tune 16,

This invention relates to brake operating mechanism for motor vehicles and the like, and more particularly to apower operating mechanism therefor.

Power brake loperating mechanisms as heretofore known in the art have been generally heavy and cumbersome and hard to control, and have been subject to rapid wear andideterioration due to the fact that the 10 connections between the source of power and the brake operating means were substantially direct connections and gave the power means little or no mechanical advantage with respect to the brake operating means.

One object of the present invention is to provide a power operated brake mechanism which is strong and reliable and which operates smoothly and eiiiciently.

Another object is to provide a brake operating mechanism in which the brake applying force is derived from the motion of a rotary part of the vehicle.

Another object is to'pro-vide such a device which is capable of accurate control with slight muscular effort on the part of the operatorand is continuously under the control of the operator. p

Another object is to provide such a device in which the force required to control the application of the brakes is a small fraction of the brake applying force.

Another object of the invention is to provide such a device in which the driving force derived from the rotary part of the vehicle ifs a small fraction of the brake applying o-rce.

Another object is to provide'a brake operating mechanism whichoperates equally well whether ,the vehicle is going forward or backward.

Another object of the invention is the provision of a power brake operating mechanism including a force multiplying unit between the driving and controlling means and the brake mechanism, whereby the driv-. ing and controlling means may be small and light, 'and the` control will be flexibleand accurate.

Another object of the invention is the provision of 'a power brake operating mecha- 1928. Serial No. 285,961. i

Jnism including a force multiplying unit, the

elements of which are normally stationary, and are in operation only when the brakes are being applied.

Other objects and advantages will be apparent from the following description taken in connection with the disclosure in the accompanying drawings.

The invention is capable of receiving a variety of mechanical expressions, one of which is shown in the accompanying drawings. It is to be expressly understood that the drawings are for purposes of illustration only and are not to be construed as a definition of the limits of the invention, reference being had to the appended claims for that purpose.

In the drawings, wherein the same reference characters are employed to designate corresponding parts vin the several gures,

'Fig. 1 is a perspective view of the brake unit assembled in operative relation with the.

automobile transmission;

Fig. 2 is a vertical longitudinal section through the power operating unit;

Fig. 3 is a vertical transverse section taken approximately on the line S-Sof Fig. 2 of the drawings; and

Fig. 4 is a vertical transverse section on line 4 4 ofFig. 2. .f

Referring iirst to Fig. 1 of the drawings numeral 10 indicates generally the usua change speed transmission'casing of the automobile with a drive shaft'll extending rearwardly therefrom, and with a gear 12 located in the rear end of the casing in constant driving relation with the drive shaft 11.

lAn auxiliary housing 13 for the power unit is provided with a iianged bracket 14 xed to the side of the transmission casing 10 by any suitable means such as the cap screws 15. The housing 13 is enlarged at its rear end to form a substantially hemispherical bell which is closed by a bearing plate lxed thereto by attaching means such as cap screws 17, and having a hollow tubular p01'- tion 18 extending within the housing to form a bearing support. An anti-friction radial and thrust bearingv 19 is mounted upon the tubular extension 18 and carries a gear 2() free- 100 ly rotatable on the bearing and with a portion eXtendin through an opening 21 in the side wall oft e transmission casing to constantly mesh with the. gear 12 in the transmission casin An anti-frlction bearing 22 is mounted within the tubular extension 18, and a corre-Y sponding anti-friction bearing 23 is retained within a tubular extension 24 of the front end plate 25 ofthe housing 13 by any suitable `means such as a cap 26. The end plate 25 is secured to the housing 13, and the cap 26 is setion thrust bearing 34 is'interposed between the shoulder 33 and the end of the tubular extension 18, to prevent rearward movement of shaft 29.

A friction drum member. 35 is ke ed to rotate with the ear 20 in any suitab e manner as by means 0% keys 36. A cooperating friction clutch member 37 is slidably keyed on the splined portion 32 of shaft 29 andis provided with a suitablel friction facing 38 which is adapted to be brought into operative engage-l ment with the friction member 35. A cross shaft 39 is journaled in the housin above the s lined portion 32 of shaft 29 an has keyed thereon a yoke 40 which embraces the clutch member 37 Vand is adapted to cooperate with an anti-friction thrust bearing 41 mounted on said clutch member. The shaft 39 extends outside of housing 13 and'has an operating arm 42 pinned thereon.

Mounted` upon the threaded portion of the shaftI 29 are two semi-cylindrical nut members 43 and 43 which are oppositely threaded in order that one may cooperate with thread.

29 and the other with thread 29 ofthe shaft 29. These nut members are provided with longitudinally extendin 44 and 44 which engage and slide wit longitudinal grooves 45 `and 45 of the housing 13 so. that the nut members are prevented from rotating with shaft 29, and any rotation of such shaft will cause the nut members to move longitudinally in opposite directions, the nut 43 moving alon the threads 29 andthe nut 43 along threa 29. f

Across shaft 46 is journaled in an enlarge# ment 47 at the forward end of housing 13 and has suitabl keyed thereon as by means ofv key 48 a yo e 49 which embraces the shaft 29 1 and is adapted to engage anti-'friction rollers 50 and 50 mounted on the forward end of the nut members 43 and 43 respectively in any suitable manner as by means of pins 61 and 61 respectively. The cross shaft 46 extends outside the housing 13 and has suitably fixed thereon an arm 52 which has an operative engagement, such as a pin and slot connection 53 and 54 with an arm 55 fixed in any suitable way to the usual brake o erating cross shaft 56 mounted in the side rails of the chassis (not shown) and connected to operate the brakes of the vehicle in any preferred manner as by means of levers 57 and 58 and links 62, 63, 64 and 65.

A drag link 66 extends rearwardly from the usual brake pedal of the automobile, not shown, and passes through an eye 67 in the upper end of arm 42. A spring 68 is mounted on the rod 66 at the rear'of the eye 67, and reacts between the eye 67 and a nut 69 threaded and pinned on the end of rod 66.

The operation of the device is as follows: Gear 12, beingfixed to the drive shaft 11,

Iis rotated by the motion of the ,vehicle and in turn causes the gear 20 and the friction drum 35 .to rotate also. When the operator desires to apply the brakes, he presses forward slightly on the brake pedal which causes the rod 66 to swing arm 42 and yoke 40 to bring the friction clutch member 37 into contact with the friction drum 35. Power is thus transmitted from drum 35 to threaded shaft 29 which causes shaft 29 to rotate and "to move the nut members 43 and 43 longituswing the shaft 46 and thus to operate the brakesthrough the arms 52, 55, shaft 56 and links -62-65 inclusive. It will be appreciated that the pressure of the nut member 43 on the yoke 49, althoughit may be as powerful as desired, depending upon the steepness of the threads of the shaft, still is always under the control of the operator and is completely and accurately' controlled by the much lighter engagement between the drum 35 and clutch member 37 through the o ration of the brake pedal. When the b e pedal is released by the operator, the clutch member 37 is separated from the drum 35 by the spring 70. The usual brake releasing-springs, not shown, then swing the yoke 49 in a counter-clockwise direction, thus slidin the active nut member back to its original ci position. If desired, a light ,spring such as shown' at 70 may be interposed between thrust bearing 34 and clutch member 37 in order maintain aslight clearance between y tral position. This backward movement ,of the active which is preferred at this time, it is obviousv ing the invention defined in the appended clutch member 37 and provide for equally efficient operation of the brake whether the vehicle is proceeding forwardly or rearwardly.

Although this invention has been illustrated in conjuction with a four-wheel braking system, it is equally applicable to an ordinary rear wheel braking system, for instance, by omitting the front Wheel brake connections. Furthermore, while the structure shown is the embodiment of the invention that other embodiments are possible within the scope of the invention, and it is to be understood that the disclosure is to be considered as illustrative only and not as limitclaims.

What is claimed is:

1. In a brake operating mechanism, a rotatable screw shaft, a friction drum independently journaled coaxially therewith, a

gear fixed on said drum and adapted to be continuously drivenl from a rotating part, a friction clutch member slidably keyed on the shaft adjacent to the drum, a thrust bearing for the shaft preventing motion of the shaft toward the drum, a compression spring between the thrust bearing and the clutch member normally maintaining said clutch members separated, means under the control of the operator for moving the clutch member into engagement with the drum to cause rotation of the shaft, a non-rotatable nut member threaded on the shaft, and connections between the nut member and brakes whereby longitudinal movement of the nut member will actuate the brakes.

2. In a brake operating mechanism for motor vehicles, a power member adapted to be driven from a rotating part of the vehicle, a friction clutch drumimounted coaxially thereof and connected to rotate therewith, a stationary bearing on which said power member is journaled, a shaft rotatably mounted in said bearing coaxially with said clutch drum and provided with a longitudinally shiftable clutch member adapted to cooperate with said clutch drum, said shaft having a thrust element thereon adjacent said bearing, a thrust bearing interposed between said thrust elementv and said fixed bearing, yielding means mounted on said shaft in cooperative relation with the shiftable clutch member for normally retaining the shiftable clutch member out of engagement with said clutch drum, said yieldin means being arranged to bear on said thrust bearing, means under the control of the operator for causing engagement of the clutch member, and connections between the shaft and the vehicle brakes whereby rotation of said shaft will apply the brakes.

In testimony whereof I have signed this specification.

FREDERICK HATHAVVAY RAGAN. 

